Riveting bucking bar anvils that are designed to be hand held by bucking bar operators must maintain an alignment on the rivet shank by sight, feel and balance. This often leaves the bucking bar operator a wide margin for errors when the bucking bar is out of alignment with the rivet shank. The traditional method for joining two or more overlapping sheets of metal together is installing rivets through numerous pre-drilled holes in the metal sheets. By positioning a rivet gun anvil to the manufactured rivet heads and referring to the second end of the rivet, a hand held rivet bucking bar anvil is positioned by a bucking bar operator on the flat diameter surface of the rivet shank protruding through a pre-drilled hole in the metal sheets. By means of a rapid burst of hammering effects from the rivet gun, energy is transferred to the head of the rivet, through the shank and onto the flat surface of the hand held bucking bar anvil.
The energy returning from the hand held bucking bar anvil to the face of the rivet shank would help shape the shank's diameter. This shaping of the shank's diameter enlarges as the energy stemming from the rivet gun and the bucking bar operator's pressure is directed toward the head of the manufactured rivet. Combining the energy and pressure shapes the new rivet head. This fastens the two or more overlapping metal sheets together with a manufactured rivet head on one end and a shop formed rivet head on the second end.
This manually controlled shaping of the rivet shank into a specific shape and size rivet head is generally guesswork and technique. An apprentice learns the guesswork and technique by applying enough pressure and trying to maintain alignment of the anvils' face at a ninety degree angle to the work surface in order to shape a new rivet head. This method of operation makes it nearly impossible to have all newly formed rivet heads conform exactly to the manufacturing specifications by manually maintaining the hand held alignment. Many newly formed rivet heads made by apprentices do not meet the manufacturing specifications and must be removed by drilling into the center of the manufactured rivet head and separating the rivet head from the shank. The shank with the (out of tolerance) rivet head is then removed from the overlapping metal sheets and a new rivet must be installed and a new head formed. This process adds cost and time to the parts being manufactured.